The principal objectives of the SPORE Lung Cancer Screening and Tissue Procurement CORE are to: (1) screen high risk smoker and ex-smoker patients identified through community and institutionally-based pulmonologists with sputum cytology to identify subjects with moderate or severe dysplasia; (2) obtain, classify, and bank sputum samples from the above; (3) support SPORE clinical investigations by obtaining bronchoscopy, serum, and urine specimens as required; and (4) maintain a registry of demographic data on all above patients. The CORE will create an archive of specimens, clinical, and demographic data for use in longitudinal investigations to evaluate hypotheses concerning the biological basis of lung carcinogenesis. The high risk population will be patients with airflow obstruction who have smoking histories of 40 or more pack years. This patient group has been selected because the risk for lung cancer has been found to increase in proportion to degree of airflow obstruction within smoking populations. The total accrual goal for the three year SPORE grant is 4,000 subjects. From prior experience, it is estimated that about 20% of these will have moderate or severe dysplasia. To enroll and instruct subjects on the selected method for sputum collection (i.e., early morning, spontaneous cough technique), the Lung Cancer Institute of Colorado's consortium of community and institutionally- based pulmonologists will be employed. Sputa collected from subjects will be processed and examined at the cytology laboratories of the following institutions: University of Colorado Health Sciences Center, Denver Veterans Administration Medical Center, Presbyterian Denver Hospital, and St. Mary's Medical Center, Grand Junction. Cytologic examinations will be performed by the SPORE pathologist panel to identify dysplastic patients for subsequent participation (if consent is obtained) in SPORE clinical studies.